The present invention relates to a novel method of continuously producing a flexible drywall joint filler of the type having a central spline portion adapted for cooperation with a joint defined between a pair of adjacent drywall panels. The drywall joint filler includes a pair of edge portions which are "feathered" or substantially thin in cross-section so that a relatively smooth surface with each exposed face of the adjacent drywall panels can be formed.
The construction industry conventionally uses drywall panels due to their relative inexpensiveness for forming durable interior walls. However, before an interior wall can be finished, (e.g. by paint, wallpaper or the like), the joints or gaps between adjacent drywall panels must be filled to provide a substantially smooth, monolithic appearance. Otherwise, the unfilled joints would present an unsightly appearance on the finished walls.
Conventional drywall panels are normally slightly tapered at the edges to facilitate the joint filling process. When adjacent drywall panels are installed, the tapered edges of each form a "v-joint" which must be filled prior to finishing the interior walls.
A prior method of filling drywall v-joints typically comprises applying an amount of joint paste compound in the v-joint and, subsequently, applying a tape, such as, an absorbent paper tape or the like over the paste compound. An additional amount of paste compound is then normally applied over the tape while it is still moist from the underlying application of paste compound and the joint is roughly smoothed with a trowel or similar tool. The paste compound is allowed to dry for a substantial period of time, for example, at least 12 hours, or overnight, and then sanded to remove high spots so that a substantially smooth finish can be provided. However, as the paste compound and absorbent tape dry, they contract thereby necessitating subsequent applications of paste compound over the tape.
Thus, as many as three or four applications of paste compound interspersed with the necessary drying time and sanding are necessary to effectuate a substantially smooth finished surface. It can therefore be appreciated that the total time for providing finished interior walls can take several days. Thus, while the drywall panels are relatively easily nailed in place, the filling of the v-joints between adjacent drywall panels is time consuming. When consideration is given to labor costs, it can be appreciated that a substantial cost is incurred by utilizing the previous method of filling drywall panel v-joints. Additionally, the prior method may be too involved for the novice thereby precluding "do-it-yourself" construction/remodeling.
However, in U.S. Pat. No. 4,157,271 (the entire disclosure of which is incorporated herein by reference), there is disclosed a flexible drywall joint filler which greatly reduces the time and effort necessary for filling joints between adjacent drywall panels. An important feature of the drywall joint filler of U.S. Pat. No. 4,157,271 is the provision of a central spline portion to cooperate with the joint defined between adjacent drywall panels. The joint filler edge portions produced according to the present invention are "feathered" or substantially thin so that when the drywall joint filler is properly installed, a substantially smooth, monolithic surface is almost instantly realized. At most, only a minimal application of paste compound is necessary to effect the desired finished appearance.
A problem has been encountered, however, in that up until the present novel method, the feathered edges of the drywall joint filler exemplified by U.S. Pat. No. 4,157,271 were practically impossible to easily and continuously produce in a commercially viable form. Thus, while a drywall joint filler has been proposed in the art to alleviate the problems associated with conventional methods of filling drywall joints, until this invention, a successful and novel method of producing such joint fillers and, particularly the feathered edges thereof, is believed to have escaped those in the art.
According to the present invention, there is provided a novel method whereby a drywall joint filler having substantially thin, "feathered" edge portions can be continuously produced. The method according to the present invention contemplates that a thermoplastic material is pre-formed by extruding it in a molten state at a predetermined extrusion rate into a continuous strip having a predetermined extrusion width. Thereafter, the continuous strip is pulled by suitable means at a rate higher than the extrusion rate thereby reducing the extrusion width between about 30-65%. In such a manner, the pre-formed strip of drywall filler which was initially extruded is pulled so that the edge portions are "feathered" to produce the desired drywall joint filler.
The strip of drywall joint filler thus extruded is cooled at its reduced width, and thereafter, can be further processed downstream. For example, the continuous strip of drywall joint filler can be applied with an adhesive and, subsequently, have a flexible backing material applied thereto so that undesirable bonding of the joint filler will be precluded. The joint filler can then be cut into predetermined lengths, packaged, and distributed to the market in any convenient or acceptable manner.
The flexible backing material utilized to prevent undesired bonding of the joint filler strips is preferably a sheet of silicone treated paper. Thus, when it is desired to install the drywall joint filler, one need only remove the protective backing material and place the joint filler in the proper location in the v-joint. The raised central spline portion of the joint filler can be utilized to find the joint or a gap defined between adjacent drywall panels and, thereafter, the edges pressed onto the drywall panels to adhesively bond the joint filler thereto.
Other aspects and advantages of the present invention will become more clear after careful consideration of the following detailed description of the preferred exemplary embodiment.